28921345 has 4 divisors (see below), whose sum is σ = 34705620. Its totient is φ = 23137072.

The previous prime is 28921339. The next prime is 28921349. The reversal of 28921345 is 54312982.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10909809 + 18011536 = 3303^2 + 4244^2 .

It is a cyclic number.

It is not a de Polignac number, because 28921345 - 2³ = 28921337 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28921345.

It is not an unprimeable number, because it can be changed into a prime (28921349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2892130 + ... + 2892139.

It is an arithmetic number, because the mean of its divisors is an integer number (8676405).

Almost surely, 2^28921345 is an apocalyptic number.

It is an amenable number.

28921345 is a deficient number, since it is larger than the sum of its proper divisors (5784275).

28921345 is an equidigital number, since it uses as much as digits as its factorization.

28921345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5784274.

The product of its digits is 17280, while the sum is 34.

The square root of 28921345 is about 5377.8569151661. The cubic root of 28921345 is about 306.9536689093.

The spelling of 28921345 in words is "twenty-eight million, nine hundred twenty-one thousand, three hundred forty-five".